1. Field of the invention
The present invention relates to an operation device for a vehicle air conditioner and, in particular, to an operation device including an illumination type operation switch.
2. Related art
Conventionally, in an operation device for a vehicle air conditioner, there generally are light transmissive front panels with light being projected from the back surfaces of the respective front panels to enhance the visibility of the operation device.
This type of an operation device for a vehicle air conditioner is structured such that lights from a plurality of light emitting elements of high luminance are guided to the central portions of the back surfaces of the respective front panels by lightguides each having a high light-transmittance, and The operation device also has switch means, each having an electric function which are disposed in the peripheral edge portions of the back surfaces of the respective front panels. A switch of this illumination type, as disclosed in Japanese Patent Publication No. 6-283077 of Heisei or Japanese Patent Publication No. 5-325703 of Heisei, illustrates a structure in which light emitting elements are respectively disposed in the central portions of the back surfaces of the respective front panels, while switch means are respectively disposed in the peripheral edge portions of the back surfaces of the respective front panels.
However, in the above-mentioned conventional operation device for a vehicle air conditioner, it is difficult to achieve both ease of operation and accurate visibility of the switches. The above-mentioned various kinds of illumination type switches are structured such that a light guide for enhancing the visibility of a light emitting element is disposed in the central portion of the back surface of each front panel. Thus, the function of the operation switch is displayed substantially in the central portion of the front panel. Moreover, the illumination of the front panel in the portion where the function of the operation switch is displayed works effectively.
However, by placing the illuminating portion of the switch in the center portion of the front panel, the switch means, which is allowed to perform its switching operation when the front panel is operated, cannot be placed in the center portion of the front panel. The switch means must be disposed in the peripheral edge of the back surface of the front panel. Therefore, when the front panel is operated, a force to incline the front panel can be applied to the front panel.
Moreover, it is difficult to operate device because the relationship between the illuminating elements and the operational switches, are reversed. On the other hand when the switch is placed in the central portion of the front panel, the operation of the switch means can be truly improved, but the illumination efficiency of the front panel is lowered, thus impairing the superiority of the operation switch of an illumination type.